Hello, while digging through the interface between ethtool and kernel, I noticed that ethtool commit 5dd7bfbc5079 ("ethtool: Add DMA Coalescing support") added new member dmac into struct ethtool_coalesce which is part of kernel UAPI but there is no kernel counterpart to this change in master, net or net-next tree.
This doesn't cause any serious trouble as with userspace structure longer than kernel thinks, kernel would simply ignore the extra member so that the feature "only" doesn't work. But I doubt such change could be accepted to kernel side of the interface as new kernel would then overflow shorter structure passed by older ethtool. Stephen Hemminger mentioned the ABI compatibility issue when this patch was submitted: https://patchwork.ozlabs.org/patch/806049/#1757846 Does it make sense to have ethtool feature without kernel counterpart? Michal Kubecek